1. Field of the Invention
The invention relates to sliding door assemblies for motor vehicles. More specifically, the invention relates to a power sliding door drive assembly for automatically moving a sliding door between an open position and a close position for a motor vehicle.
2. Description of Related Art
In various types of motor vehicles, including minivans, delivery vans, and the like, it has become common practice to provide a vehicle body with relatively large side openings that are located immediately behind front doors and which are opened and closed with a sliding door. The sliding doors are typically mounted with hinges on horizontal tracks on the vehicle body for guided sliding movement between a close position flush with the vehicle body closing the side opening and an open position located outward of and alongside the vehicle body rearward of the side opening. The sliding doors may be operated manually or with a power drive assembly. When there is a power drive assembly for the sliding door, the power drive assembly works electronically by activating a switch within the motor vehicle or by activating a remote, typically located on a key fob. These power drive assemblies are becoming more and more popular. Although having the ability to press a button and open a sliding door is convenient, there are certain disadvantages.
In a standard arrangement of a power drive assembly a pair of cable sections, which may be separate or part of a common cable, each have one end anchored on the sliding door and an opposite end anchored on a cable drum. The cable sections are wound about the cable drum in opposite directions. The cable drum is axially mounted on a shaft or drive pin which is rotated by a reversible electric motor in a first or second direction depending on whether the sliding door is to be opened or closed. Rotation of the cable drum winds one cable section onto the cable drum and pays the other cable section off the cable drum.
In order to preserve the cable, the cable drum is formed with helical grooves intended to receive the respective cable section when it is wound thereon. It is important that the cable wind-up smoothly, without turns one atop the other, so that the cable itself does not chafe and prematurely wear out, and in order to keep the assembly as compact as possible.
The problem with this arrangement is that the cable is pulled at an angle at least toward the end of a windup operation and at the beginning of an unwind operation, so it is fairly common for the cable to jump out of its groove, causing a chafing problem and possibly leading to binding of the cable drum. It is, therefore, desirable to provide a sliding door drive assembly including support guides extending from a cable drum to guide first and second cables toward and away from the cable drum during operation of the sliding door drive assembly. It is also desirable to provide a sliding door drive assembly including a position sensor to monitor the position of the sliding door.